1. Technical Field
The present invention relates to an organic EL light-emitting device and an electronic apparatus including the light-emitting device.
2. Related Art
EL (electroluminescence) light-emitting devices, particularly organic EL light-emitting devices, feature the ease of reducing the weight and thickness, and are increasingly being used as image forming elements of a display or as light-emitting pixels of an image-forming apparatus that transfers an image formed with a line head module to a medium with a photosensitive drum.
It is desired that monochromaticity is increased in order to increase the color specification range in the field of displays, and in order to prevent the degradation (blur) of formed images resulting from wavelength dispersion of the SELFOC® lens array used in imaging optical systems in the field of image-forming apparatuses. For example, Japanese Unexamined Patent Application Publication No. 06-275381 has disclosed a bottom emission light-emitting device to achieve these objects. In this light-emitting device, a dielectric mirror including alternately formed low-refractive-index thin layers and high-refractive-index thin layers is disposed under the luminescent layer so that light having a specific wavelength is strengthened by interference, and thus enhances the monochromaticity.
In addition, in order to increase the lifetime of or reduce the power consumption of organic EL light-emitting devices, it is desired that the aperture ratio, which is the ratio of the area from which light is actually emitted to the area of the display region, is increased, and for example, Japanese Unexamined Patent Application Publication No. 2004-186043 has disclosed a top emission organic EL light-emitting device including a luminescent layer over the pixel driving portion.
However, the dielectric mirror is formed by repeating the deposition of thin layers, so that the underlying layer is damaged by, for example, heating. It is therefore difficult to provide a dielectric mirror over the luminescent layer, which is made of an organic material. Thus it is difficult to provide a dielectric mirror in a top emission type, which emits light from the upper side of the luminescent layer.